CVE-2020-6007: Philips Hue Bridge V2 RCE Vulnerability

CVE-2020-6007 Overview

CVE-2020-6007 is a heap-based buffer overflow vulnerability affecting Philips Hue Bridge model 2.X devices. The vulnerability exists in how the device handles ZCL (ZigBee Cluster Library) strings during the commissioning phase. When an overly long ZCL string is processed, the device fails to properly validate the input length, leading to a heap-based buffer overflow condition that can be exploited for remote code execution.

This vulnerability is particularly concerning as it affects IoT smart home devices that are often deployed in residential and enterprise environments. Successful exploitation could allow an attacker within adjacent network range to compromise the Hue Bridge, potentially gaining control over connected smart lighting systems and establishing a foothold in the target network.

Critical Impact

Remote code execution on Philips Hue Bridge devices through heap-based buffer overflow during ZigBee commissioning, enabling attackers to compromise smart home infrastructure from adjacent networks.

Affected Products

• Philips Hue Bridge V2 Firmware (versions prior to and including 1935144020)
• Philips Hue Bridge V2 hardware

Discovery Timeline

• 2020-01-23 - CVE-2020-6007 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-6007

Vulnerability Analysis

This vulnerability is classified under CWE-122 (Heap-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). The flaw resides in the ZigBee protocol implementation within the Philips Hue Bridge V2 firmware. During the device commissioning phase, when the bridge processes ZCL strings used for device identification and pairing, insufficient bounds checking allows an attacker to provide a maliciously crafted string that exceeds the allocated buffer size.

The heap-based nature of this overflow means that memory corruption occurs in dynamically allocated memory regions, which can be leveraged to overwrite adjacent heap metadata or other critical data structures. This type of vulnerability is particularly dangerous as it can lead to arbitrary code execution with the privileges of the affected process.

The attack requires the adversary to be within adjacent network range (typically ZigBee radio range) and requires some user interaction during the commissioning process. Despite these requirements, the potential for complete device compromise makes this a significant security concern.

Root Cause

The root cause of CVE-2020-6007 is improper input validation in the ZCL string parsing routine. The firmware fails to enforce proper length limits when copying ZCL string data into heap-allocated buffers during the commissioning phase. This allows specially crafted input to overflow the destination buffer and corrupt adjacent memory regions.

The ZigBee protocol implementation does not adequately sanitize incoming data before processing, violating secure coding principles for embedded systems. The lack of bounds checking on string length parameters creates a condition where an attacker-controlled string can overwrite heap memory beyond the intended allocation.

Attack Vector

The attack vector requires adjacent network access, as ZigBee operates on the 2.4 GHz radio frequency with limited range (typically 10-100 meters). An attacker must be within ZigBee communication range of the target Hue Bridge and must initiate or intercept a commissioning sequence.

The exploitation flow involves:

1. The attacker positions themselves within ZigBee radio range of the target Philips Hue Bridge
2. During a device commissioning phase (when new bulbs or devices are being paired), the attacker injects a maliciously crafted ZCL string
3. The oversized string triggers a heap-based buffer overflow when processed by the bridge
4. Through careful memory manipulation, the attacker achieves remote code execution on the device

The vulnerability mechanism relies on the ZigBee commissioning process, where devices exchange identification and capability information. The heap overflow is triggered when the bridge attempts to parse an overly long ZCL string attribute, writing beyond allocated memory boundaries and potentially corrupting control flow data. For detailed technical analysis, refer to the Check Point Research Article.

Detection Methods for CVE-2020-6007

Indicators of Compromise

• Unexpected behavior or crashes of Philips Hue Bridge devices
• Unexplained ZigBee network traffic or commissioning attempts when no legitimate pairing is occurring
• Anomalous outbound network connections from the Hue Bridge to unknown external hosts
• Modified firmware or configuration files on the bridge device

Detection Strategies

• Monitor ZigBee network traffic for unusually large ZCL string transmissions during commissioning phases
• Implement network segmentation to isolate IoT devices and enable easier traffic monitoring
• Use intrusion detection systems (IDS) to identify anomalous patterns in smart home network segments
• Deploy SentinelOne agents on network infrastructure to detect lateral movement attempts originating from compromised IoT devices

Monitoring Recommendations

• Establish baseline ZigBee traffic patterns and alert on deviations
• Monitor the Hue Bridge firmware version and ensure automatic updates are enabled
• Log and review all commissioning events on smart home networks
• Implement network behavior analysis for IoT device segments

How to Mitigate CVE-2020-6007

Immediate Actions Required

• Update Philips Hue Bridge V2 firmware to version newer than 1935144020 immediately
• Disable commissioning mode when not actively pairing new devices
• Isolate IoT devices on a separate network segment with restricted access
• Review and audit all devices currently paired with the Hue Bridge

Patch Information

Philips has released firmware updates addressing this vulnerability. Users should update their Hue Bridge devices to the latest available firmware version through the Philips Hue mobile application or web interface. The Philips Hue Release Notes provide details on firmware updates and security fixes.

Automatic updates should be enabled to ensure timely application of security patches. Organizations deploying Philips Hue devices in enterprise environments should establish a patch management process for IoT devices.

Workarounds

• Limit physical proximity access to ZigBee-enabled areas to reduce attack surface
• Disable commissioning mode and keep it disabled except during legitimate device pairing operations
• Implement network segmentation to isolate smart home devices from critical network infrastructure
• Consider deploying additional RF shielding in sensitive environments to limit ZigBee signal propagation

# Network segmentation example using VLAN configuration
# Isolate IoT devices on a dedicated VLAN

# Create IoT VLAN
vlan 100
  name IoT_Devices
  
# Apply access control list to restrict IoT device communication
access-list 100 permit tcp any host 10.0.100.1 eq 443
access-list 100 deny ip any 10.0.0.0 0.255.255.255
access-list 100 permit ip any any